PC help needed!

[johncomic]

I run ESET NOD antivirus, Spybot and Malwarebytes on my PC, all recommended by the shop where I get the beast serviced. Despite running those three protective programs, a bug has gotten into my machine. Here's how I know:

- I can't update Spybot
- I can't get into Spybot's OR Malwarebytes's websites, my browser “can't find them”
- my Google searches are getting hijacked to unrelated undesired locations
- occasionally fake security warnings pop up

So something is pulling nasty tricks but my anti programs can't locate it.

Besides running these things, I have also run Avira, Stinger, and Combofix at other people's recommendation, all to no avail. The IT guys at my office tried to help. Malwarebytes support guy has been contacting me sporadically for weeks. This week I finally took it in to the shop. Just got it back today -- they told me that the updating and browser thwarting was all fixed. But they also admitted that they didn't know where the bug came from, or exactly what it was, or how to stop it from coming back. But as soon as I got it home, ALL the above problems were still there! So either the shop lied to me, or else by the most amazing stupid luck the bug jumped back in off the internet within minutes of me hooking the machine up at home!

I'm on the verge of buying a new computer (which we really can't afford now) as a “solution” to this problem -- hoping that the same mystery bug won't infect IT too! I have banking and income taxes and whatnot that I need to do, and I'm reluctant to do them on a machine that I know is compromised.

Please does ANYONE know what the eff is going on with my PC and how to fix it? I realize that if it has The Professionals stumped then odds are not in my favour, but no harm in asking, right?